Vehicle Control Systems and Methods and Related Vehicles

ABSTRACT

Systems for controlling the speed and direction of vehicles, including vehicles that have low to zero turning radius capability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/346,690, filed Aug. 25, 2014, a national phase application under 35U.S.C. § 371 of International Application No. PCT/US2011/052845, filedSep. 22, 2011, both of which are specifically incorporated by referencewithout disclaimer.

BACKGROUND

Embodiments of the invention relate generally to vehicles that have lowto zero turning radius capability. In the art, zero turning radiusvehicles are often described as ZTR vehicles, although this name hasalso been used to described vehicles capable of a turning radius that isnot precisely zero. More specifically, embodiments of the inventionrelate to steering systems for such vehicles, to steering and speedcoordination systems for such vehicles, to vehicles that comprises oneor both types of systems, and to methods of coordinating steering andspeed inputs in operating a vehicle.

SUMMARY

In one respect, the invention is a vehicle control system, embodimentsof which comprise a first flexible member configured to be coupled to afirst steering input member; a control member operatively engaged withthe first flexible member; and a first integration link coupled to thecontrol member and configured to be coupled to a first drive unit. Thecontrol member may comprise gear teeth. The control member may be arigid structure. The control member may be operatively engaged with thefirst flexible member such that movement of the first flexible memberresults in movement of the control member. The first integration linkmay be a rigid structure and may pivot laterally as a result of movementof the control member, which may be rotational movement. The vehiclecontrol system may have a second flexible member configured to becoupled to a second steering input member, and a second integration linkcoupled to the control member and configured to be coupled to a seconddrive unit. The vehicle control system may have first and secondintegration members coupling the control member to the first and secondintegration links, respectively. The vehicle control system may havefirst and second speed input members responsive to movement of a speedinput device, such as a pedal, and coupled to the first and secondintegration links, respectively, such that movement of the speed inputdevice will cause forward or rearward movement of the links.

In another respect, the invention is a vehicle control system,embodiments of which comprise a first steering system for a firststeerable wheel, wherein the first steering system comprises a firststeering input member configured to be coupled to a steering inputdevice; a control member configured to receive a steering input from thefirst steering input member; and a first integration link coupled to thecontrol member and configured to be coupled to a first drive unit. Thefirst control member may be a rigid structure and may rotate as a resultof receiving the steering input. The first steering member may be ageared member that moves as a result of movement of a rack-and-pinionassembly coupled to a steering input device, such as a steering wheel.The first integration link may be a rigid structure and may pivotlaterally as a result of movement of the control member. The vehiclecontrol system may have a second integration link coupled to the controlmember and configured to be coupled to a second drive unit. The vehiclecontrol system may have first and second integration members couplingthe control member to the first and second integration links,respectively. The vehicle control system may have first and second speedinput members responsive to movement of a speed input device, such as apedal, and coupled to the first and second integration links,respectively, such that movement of the speed input device will causeforward or rearward movement of the links.

In another respect, the invention is a vehicle control system,embodiments of which comprise a control member that will move as aresult of movement of a steering input device; a first integration linkcoupled to the control member and configured to be coupled to a firstdrive unit; and a first integration member coupled to the firstintegration link such that rotational movement of the control memberwill cause movement of the first integration member, which will causemovement of the first integration link. In some embodiments, the firstintegration member is not attached to a rigid link that extends forwardof the control member. In some embodiments, the vehicle control systemis configured so as to not send a steering signal forward of the controlmember. The vehicle control system may have a second integration linkcoupled to the control member and configured to be coupled to a seconddrive unit. The first and second integration links may be rigid and mayhave each have a slot that is substantially straight along at least themajority or all of its length. The vehicle control system may also havesecond integration member operatively engaged with the control memberand coupled to the second integration link such that rotational movementof the control member will cause movement of the second integrationmember, which will cause movement of the second integration link. Thevehicle control system may have first and second speed input membersresponsive to movement of a speed input device, such as a pedal, andcoupled to the first and second integration links, respectively, suchthat movement of the speed input device will cause forward or rearwardmovement of the links.

In another respect, the invention is a vehicle control system,embodiments of which comprise a gear that will rotate in response tomovement of a steering input device; a control member operativelyengaged with the gear and configured to rotate as a result of rotationof the gear; a first integration link coupled to the control member andconfigured to be coupled to a first drive unit; and a first integrationmember operatively engaged with the control member and coupled to thefirst integration link such that rotational movement of the controlmember will cause movement of the first integration member, which willcause movement of the first integration link. The vehicle control systemmay have a second integration link coupled to the control member andconfigured to be coupled to a second drive unit. The first and secondintegration links may be rigid and may have each have a slot that issubstantially straight along at least the majority or all of its length.The vehicle control system may also have second integration memberoperatively engaged with the control member and coupled to the secondintegration link such that rotational movement of the control memberwill cause movement of the second integration member, which will causemovement of the second integration link. The vehicle control system mayhave first and second speed input members responsive to movement of aspeed input device, such as a pedal, and coupled to the first and secondintegration links, respectively, such that movement of the speed inputdevice will cause forward or rearward movement of the links.

Embodiments of the present vehicle control systems, including thoseillustrated in the figures below, are configured to reduce the speed ofthe vehicle of which it is a part (specifically the outboard drivewheel) when it enters a sufficiently extreme turn (e.g., one in which asteerable wheel of the vehicle (such as one engaging the ground througha tire) can be turned no further) under a constant speed input.Embodiments of the present vehicle control systems, including thoseillustrated in the figures below, are configured to provide correctsteering of the vehicle of which it is a part in forward and reverse fora given steering input (meaning the vehicle will follow the same arc fora given turn in forward as it will in reverse).

In another respect, the invention is a vehicle that includes any of thepresent vehicle control systems.

In another respect, the invention is a method of integrating a steeringinput with a speed input in operating a vehicle, where the methodcomprises: receiving a steering input from a steered wheel that isconfigured to engage the ground (such as through a tire); positioning afollower along a cam of a speed input member as a result of thereceiving; moving the speed input member by manipulating a speed inputdevice (such as a pedal); and moving an integration link coupled to thefollower as a result of moving the speed input member. The cam may be aslot and the follower may be a coupling member, and the method mayinvolve a second speed input member with a second cam and a secondintegration link coupled to a second follower that can be positionedalong the second cam.

In another respect, the invention is a method of integrating a steeringinput with a speed input in operating a vehicle, where the methodcomprises: receiving a steering input from a steering input device (suchas a steering wheel); positioning a follower along a cam of a speedinput member as a result of the receiving; moving the speed input memberby manipulating a speed input device (such as a pedal); and moving anintegration link coupled to the follower as a result of moving the speedinput member. In some embodiments, a steering signal is not sent forwardof a control member that is coupled to the integration link. The cam maybe a slot and the follower may be a coupling member, and the method mayinvolve a second speed input member with a second cam and a secondintegration link coupled to a second follower that can be positionedalong the second cam.

Any embodiment of any of the present systems, devices, and methods mayconsist of or consist essentially of—rather thancomprise/include/contain/have—the described features or steps. Thus, inany of the claims, the term “consisting of” or “consisting essentiallyof” may be substituted for any of the open-ended linking verbs recitedabove, in order to change the scope of a given claim from what it wouldotherwise be using the open-ended linking verb.

The feature or features of one embodiment may be applied to otherembodiments, even though not described or illustrated, unless expresslyprohibited by this disclosure or the nature of the embodiments.

Details associated with these embodiments and others are provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate by way of example and not limitation.Identical reference numerals do not necessarily indicate an identicalstructure. Rather, the same reference numeral may be used to indicate asimilar feature or a feature with similar functionality. Every featureof each embodiment is not always labeled in every figure in which thatembodiment appears, in order to keep the figures clear. The embodimentsof the present devices and systems (and their components) shown in FIGS.1-15 are drawn to scale.

FIG. 1 is a perspective view of a lawn and garden type vehicle;

FIG. 2 is a perspective view of the chassis and vehicle controlassemblies of the vehicle of FIG. 1;

FIG. 3 is a partial perspective view of the control assembly of thevehicle of FIG. 1;

FIG. 4 is a partial perspective view of the control assembly of thevehicle of FIG. 1;

FIG. 5 is a partial perspective view of the steering assembly of thevehicle of FIG. 1;

FIG. 6 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a neutral steering input and a neutral speedinput;

FIG. 7 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a left turn steering input and a neutralspeed input;

FIG. 8 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a right turn steering input and a neutralspeed input;

FIG. 9 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a neutral steering input and a forward speedinput;

FIG. 10 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a left turn steering input and a forwardspeed input;

FIG. 11 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a right turn steering input and a forwardspeed input;

FIG. 12 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a neutral steering input and a reverse speedinput;

FIG. 13 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a left turn steering input and a reversespeed input;

FIG. 14 illustrates a top view of the control and steering assemblies ofthe vehicle of FIG. 1 with a right turn steering input and a reversespeed input; and

FIG. 15 illustrates a partial top view of another embodiment of one ofthe present control assemblies.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “contain” (and any form of contain, such as “contains” and“containing”), and “include” (and any form of include, such as“includes” and “including”) are open-ended linking verbs. Thus, avehicle that “comprises” a steering input member; a first control memberoperatively engaged with the steering input member; a first steeringlink coupled to the first control member and to a steering system for afirst steered wheel; and a first integration link coupled to the firstcontrol member and to a control system for a first drive unit, is avehicle that possesses the listed elements, but is not prohibited frompossessing elements that are not listed (such as a steerable structure).

Likewise, an element of a device or apparatus that “comprises,” “has,”“contains” or “includes” one or more features possesses those one ormore features, but is not limited to possessing only those one or morefeatures. Furthermore, a structure that is configured in a certain waymust be configured in at least that way, but also may be configured in away or ways that are not specified.

The terms “a” and “an” are defined as one or more than one unless thisdisclosure explicitly requires otherwise. The term “coupled” is definedas connected, although not necessarily directly, and not necessarilymechanically. The term “substantially” and its variations (e.g.“approximately” and “about”) are defined as being largely but notnecessarily wholly what is specified (and include wholly what isspecified) as understood by one of ordinary skill in the art. In anydisclosed embodiment, the terms “substantially,” “approximately,” and“about” may be substituted with “within [a percentage] of” what isspecified, where the percentage includes 0.1, 1, 5, and 10 percent.

General Configuration

Referring now to the figures, FIG. 1 illustrates a vehicle 10, such as alawn and garden tractor. The vehicle 10 includes a prime mover 12, suchas an engine, that is mounted to a structural frame or frame 14. Thevehicle 10 includes drive wheels 16, such as left and right rear drivewheels that are coupled to the frame 14. The drive wheels 16 are coupledto the engine 12 through a transmission system to provide locomotion tothe vehicle 10. The vehicle 10 also has steerable structures 18, such asright and left front wheels, which may be non-driving wheels. Otherembodiments of the vehicles have only one steerable structure (e.g.,three-wheeled all-terrain vehicles). Furthermore, in some embodiments,steerable structures such as skis may be used instead of wheels.

The frame 14 supports an operator station comprising a seat 22. Vehicle10 also includes a mower deck 26 mounted to the vehicle 10 in anysuitable manner. In some embodiments, the invention is applicable toother types of vehicles, including but not limited to utility vehicles,off road vehicles, tractors, golf carts, and even automobiles.

As shown in FIG. 5, the front steerable wheels 18 are coupled to theframe of the vehicle through a rack and pinion assembly 19 coupled to(and, more specifically, mounted on) the frame 14. The steerable wheels18 are also coupled to a steering assembly 20, which is configured tocontrol the direction they turn as discussed more fully below. In theembodiment of the present vehicles shown in the figures, the frontwheels are the steerable wheels 18 and the rear wheels are the drivewheels 16. However, one skilled in the art will understand that the rearwheels may be the steerable wheels and the front wheels may be the drivewheels in other embodiments. Likewise, the front wheels may be bothsteerable and drivable.

A steering input device 24 (which is part of the embodiment of thesteering assembly 20 shown in the figures) and a speed control device 71(which is part of the embodiment of the speed control assembly 70discussed below) are located near the seat 22 (FIG. 1) so that they areaccessible to the operator of the vehicle. An operator may apply asteering input to the steering input device 24, which transfers thesteering input to the steering assembly 20. Steering input device 24 maytake the form of a conventional steering wheel. However, the steeringinput device 24 may be another suitable steering device, including, butnot limited to, a steering rod or joystick (not shown).

Speed control devices 71 and 79 provide a forward and reverse speedinput, respectively, to the balance of the speed control assembly 70,and (at least in part) regulate the forward and reverse speed of thevehicle 10. In certain embodiments, speed control devices 71 and 79 maytake the form of a single pedal, such as a treadle pedal arrangementmounted on a single shaft. In such an embodiment, the speed controldevice can be rocked forward to select forward drive, or rocked backwardto select reverse drive. Speed control devices 71 and 79 may be biasedtoward a central position that corresponds to a neutral or stationarycondition.

Vehicle 10 also includes a control system 40 that is configured tointegrate a steering input received by the steering assembly 20 via thesteering input device 24 with a speed input received by the speedcontrol assembly 70 (discussed below) via the speed control devices 71and 79 to drive and help steer the vehicle 10. The configurations of thepresent steering assemblies, speed control assemblies and integrationdevices allow the vehicle to make small- to zero-radius turns.

The left and right drive wheels 16 are driven through a transmissionsystem that, in the depicted embodiment, comprises left and right driveunits 59. Vehicle 10 includes a speed control assembly 70 that controlsthe direction and magnitude of rotation of the rear drive wheels 16. Thedrive units 59 may comprise hydrostatic transmissions (as shown) orelectric motors, both of which are well known in the art. Each drivewheel 16 is mounted on a hub coupled to an output shaft of each driveunit 59. The drive units 59 may also be transmissions of thecontinuously variable type, capable of providing a continuous range ofratios from forward to reverse. Examples of a suitable transmissionutilizing a ratio varying-device, or variation, in conjunction with anepicyclic shunt gear to provide a geared neutral facility is describedin International Application PCT/GB03/00332, published under WO03/064892, and International Application PCT/GB03/02332, published underWO 03/100295, both of which are incorporated by reference for thosedescriptions. The drive units 59 may be used to independently drive thedrive wheels 16 at rates and directions that propel as well as helpsteer the vehicle.

The driver dictates the speed and direction of the vehicle 10 bymanipulating steering input device 24 and speed control device 71, whichtransmit the steering and speed inputs received from the driver tocontrol system 40, the operation of which is described in more detailbelow. In the embodiment of vehicle 10 shown in the figures, the amountof torque that the rear drive wheels must produce to turn the vehicle 10is reduced because front wheels are steerable wheels 18. In contrast,the drive wheels 16 of some conventional ZTR vehicles with non-steerablecastor wheels must produce significant torque to cause the castor wheelsto react and point in the desired direction.

In the embodiment of vehicle 10 shown in the figures, the right and leftdrive wheels 16 are coupled to frame 14 such that their direction isfixed and their rotational axes are substantially in constant alignment.In contrast, the front steerable wheels 18 are coupled to the frame 14in a way that gives them the ability to change direction. The use of asubstantially-true Ackermann steering geometry (which can be achievedusing some of the embodiments discussed below) can help to avoidscrubbing rubber from the tire tread on the outboard wheel or damagingvegetation under the front wheels.

Steering Assembly

Aspects of steering assembly 20 are depicted in, e.g., FIGS. 2 and 5-14.One function of the steering assembly 20 is to couple the steering inputdevice 24 to the front steerable wheels 18 to aid in guiding vehicle 10.Another function of the steering assembly 20 is to provide a steeringinput from a steerable wheel 18 to the control system 40, which cancoordinate that steering input with a speed input received through speedcontrol device 71. Another function of the steering assembly 20 is itsability to turn the steerable wheels of the vehicle 10, even in a zeroturning radius mode (or a small turning radius mode), while receiving aninput from a conventional steering input device such as a steeringwheel.

In one embodiment, the steering assembly 20 includes a steering shaft 30coupled to steering input device 24 and rack and pinion assembly 19.Steering shaft 30 includes at least three segments in the depictedembodiment: 30 a, which extends from steering input device 24 to a firstu-joint 31; 30 b, which extends from first u-joint 31 to second u-joint33; and 30 c, which is disposed between u-joint 33 and u-joint 35.U-joint 31 allows the angle of steering shaft segment 30 a to beadjusted relative to steering shaft segment 30 b, so as to best suit agiven rider. Electric power assist assembly 34 is disposed betweenu-joints 33 and 35 and includes an electric motor (which receives powerfrom a battery coupled to the vehicle (not shown)) that functions tohelp turn steering shaft segment 30 c. The steering shaft 30 and rackand pinion assembly 19 take part in transmitting the steering inputreceived through the steering input device 24 to front wheel assemblies50, the operation of which is described in more detail below. In certainembodiments, front wheel assemblies 50 are configured to provideAckermann steering so that the inner front wheel turns about a smallerradius than the outer front wheel.

Referring specifically to FIG. 5, in one embodiment, the couplingbetween the steering shaft 30 and the front wheel assemblies isaccomplished using rack and pinion assembly 19, which includes links 21coupled to steering input members 23, which in the depicted embodimentis a steering input gear. Steering input members 23 are engaged withsteering gear members 25, which are coupled to wheel supports (yokes, inthis embodiment) 27. As steering shaft 30 is rotated, links 21 areshifted laterally to rotate steering input members 23, which in turncause wheel supports 27 and front steerable wheels 18 to turn. In thisway, steering assembly 20 is configured to receive a rotational steeringinput and translate it into two separate linear outputs that aretransmitted substantially laterally to two different steerable wheelassemblies (50, in this embodiment). The steering input member 23 andsteering gear member 25 of a given front wheel assembly 50 are connectedto the same structural member 15 of frame 14 such that their positionsrelative to each other are fixed.

In this embodiment, each steering input member 23 is coupled (and, inthe depicted embodiment, directly connected) to a flexible member 80. Incertain embodiments, each flexible member 80 is configured as a cable.In other embodiments, flexible members 80 may be configured as a belt,chain, or other suitable device. In certain embodiments, a singleflexible member may be coupled to both steering input members 23. Therotation of steering input members 23 causes flexible members 80 tomove, as will be discussed in more detail below.

Steering assembly 20 is configured such that rotation of the steeringinput device 24 and steering shaft 30 causes rotation (and morespecifically, taking into account manufacturing tolerances and play inthe u-joints, near-simultaneous rotation) of front steerable wheels 18.In certain exemplary embodiments, the steering input device 24 andsteering shaft 30 may be rotated through about 120 degrees of movement.For example, the steering input device 24 may be selectively rotated 60degrees in a first direction with respect to a neutral (straight-ahead)steering position and 60 degrees in a second direction. However, thesteering input device 24 and steering shaft 30 may be configured forrotation through any range of angles suited to a given application.

Speed Control Assembly

Referring now to FIGS. 1-4, speed control assembly 70 comprises speedcontrol devices 71 and 79. In this embodiment speed control device 71 isconfigured to control the forward speed of vehicle 10, while speedcontrol device 79 is configured to control the rearward speed of vehicle10. It is understood that in other embodiments, a single speed controldevice can be utilized to control both forward and rearward speed ofvehicle 10. While the effects of manipulating speed control device 71will primarily be discussed, it is understood that the manipulation ofspeed control device 79 will have similar but opposite effects oncontrol system 40 and vehicle 10 (e.g., a reverse speed input ratherthan a forward speed input).

Speed control device 71 is coupled to shaft 76 such that when speedcontrol device 71 is pressed forward, shaft 76 rotates counter-clockwise(when viewed from the end of shaft 76 nearest speed control device 71).As shaft 76 rotates counter-clockwise, coupling members 75 are movedtoward the front of vehicle 10 (e.g., away from drive units 59).Coupling members 75 are, in the depicted embodiment, rigid links (e.g.,rods) that are coupled to a pair of speed input members 78, which eachcomprise a slot 77. As coupling members 75 are shifted forward, speedinput members 78 are rotated such that the inner ends 49 of slots 77 areshifted toward the front of the vehicle 10 (e.g., when viewed fromabove, the right speed input member 78 rotates clockwise and the leftspeed input member 78 rotates counter-clockwise).

As previously discussed, flexible members 80 move as a result of asteering input being provided through steering input device 24. Flexiblemembers 80 are coupled (and, in the depicted embodiment, directlyconnected) to a control member 81 such that movement of flexible members80 causes rotation of control member 81. For example, when steeringinput device 24 is rotated clockwise (when viewed from above) to effecta right turn, flexible members 80 will cause control member 81 to rotatecounter-clockwise (when viewed from above). In the depicted embodiment,control member 81 comprises a geared structure having teeth that aresubstantially equidistant from the rotational axis of the controlmember, and that surround at least 50 percent (more specifically, atleast 75 percent, and even more specifically at least 90 percent) of thecontrol member. Control member 81 includes a flexible member connectorplate 83 a (which has an at least partially circular shape) that isattached to a geared plate 83 b and to which flexible members 80 aredirectly connected. In this way, the positions of the flexible membersdo not impair the contact between control member 81 and integrationmembers 36, discussed in more detail below.

Control member 81 is engaged with at least one integration member thatis a rigid structure configured to affect the position of theintegration links relative to the speed input members and that in thisembodiment comprises two integration members 36 such that rotation ofcontrol member 81 also causes rotation of integration members 36.Therefore, as steering input device 24 is rotated to initiate a turn,integration members 36 also rotate. Integration members 36 are coupledto integration links 44 via coupling members 45 such that rotation ofintegration members 36 moves integration links 44 such that theintegration links pivot laterally about the point of connection betweendrive links 104 (to which the integration links are coupled) and controlmechanisms 106 for drive units 59. Although not highlighted in thefigures, a sealed ball bearing may be used to connect each drive link toa respective control mechanism. In the depicted embodiment, integrationmembers 36 comprise geared structures having teeth that aresubstantially equidistant from the rotational axis of the respectiveintegration member, and that surround at least approximately 50 percentof the respective integration member. In the depicted embodiment, theturning radius of geared plate 83 b (or, more generally, of controlmember 81) is greater than the turning radii of integration members 36.

In the depicted embodiment, control member 81 and integration members 36are rotatable in one of more parallel planes. In addition, integrationlinks 44 and speed input members 78 can laterally pivot in the (same)one or more parallel planes. In the embodiment shown, speed inputmembers 78 comprise a plurality of rollers 98 configured to followrespective openings 99 in panel 97. Openings 99 may have a curved shape,and the shape may be comprised of differently-shaped curved segments.Each roller 98 may include a sealed ball bearing (not shown).

In certain embodiments, integration links 44 are coupled to integrationmembers 36 via coupling members 45 (which may be characterized asfollowers) that engage the slots 43 (which may be characterized as camsor cam slots) in integration links 44. In certain embodiments, slots 43are straight along substantially their entire length. In someembodiments, a given coupling member 45 is attached to (e.g., bolted to,threaded into, welded to) or even integral with integration member 36and couples (more specifically, directly connects) integration member 36to integration link 44 by extending vertically through slot 43 ofintegration link 44. Coupling members 45 may include bolts or pins withthreaded ends that may be coupled to integration links 44 via a threadedcoupling.

In the depicted embodiment, coupling members 45 are coupled tointegration members 36 so that as integration members 36 rotate,coupling members 45 move in an arc, which movement includes both aforward or a backward component (towards the front or back of vehicle10) and a lateral component (towards one side of vehicle 10). As aresult, coupling members 45 can slide forward or back within slots 43and can also cause integration links 44 to pivot laterally (as discussedabove) by exerting a force on the side of slots 43.

Integration links 44 are also coupled to speed input members 78 viaspeed input coupling members 85 (which may be characterized asfollowers). In one embodiment, speed input coupling members 85 are pinsthat extend vertically from integration links 44 and through speed inputmembers 78.

Coupling members 45 act on right and left integration links 44, whichare laterally pivoted and, through speed input coupling members 85,engage slots 77 (which may also be characterized as cams or cam slots)of speed input members 78 in different locations within slots 77. Forexample, when steering input device 24 is placed in a neutral positionas shown in FIG. 6, integration links 44 are arranged so that they areproximate to the outer ends 51 of slots 77. However, as steering inputdevice 24 is turned to the left as shown in FIG. 7, left integrationlink 44 (and speed input coupling member 85) is moved proximate to innerend 49 of slot 77, while right integration link 44 is moved generallysideways (or, more specifically, pivoted laterally counter-clockwise)toward inner end 49 to a lesser degree. Similarly, when steering inputdevice 24 is turned to the right, as shown in FIG. 8, right integrationlink 44 is moved proximate to inner end 49 of slot 77, while leftintegration link 44 is moved generally sideways (or, more specifically,pivoted laterally clockwise) toward inner end 49 to a lesser degree.

As discussed more fully below, the manipulation of speed control device71, along with steering input device 24, affects the rotational speedand direction of rotation of drive wheels 16.

Control System

Embodiments of the present vehicle control systems, including thoseillustrated in the figures, are configured to reduce the speed of theoutboard drive wheel during a sufficiently extreme turn under a constantspeed input. Embodiments of the present vehicle control systems,including those illustrated in the figures, are configured to providecorrect steering of the vehicle of which it is a part in forward andreverse for a given steering input. These configurations may be achievedusing, for example, the embodiments of control system 40 shown anddescribed in this disclosure, including, in at least some embodiments,through the operation of the control member, the integration members,the integration links, and the speed input members.

FIGS. 6-8 illustrate views of control system 40 in a neutral speedposition for speed control devices 71 and 79 and with different steeringinputs from steering input device 24. With speed control devices 71 and79 in a neutral speed position, control system 40 is configured so thatmanipulation of steering input device 24 does not cause right or leftintegration link 44 to be shifted towards the front or rear of vehicle10. For example, each slot 77 of the speed input members 78 is slightlycurved at a radius equivalent to the combined effective length ofintegration link 44 and a drive link 104 (the distance between slot 47and the connection point where drive link 104 connects to drive unit59). Therefore, right and left drive units 59 will not be manipulated tocause rotation of either drive wheel 16 based on a steering input alone.The relationship between the position of integration links 44 and theoutput of drive units 59 is discussed more fully below.

As shown in FIG. 3, each integration link 44 is coupled to a drive link104, which is in turn coupled to a control mechanism 106 for drive unit59. Integration link 44 and drive link 104 may be integral components incertain embodiments. As explained more fully below, integration link 44delivers an integrated steering and speed signal (when a speed signalhas been inputted) to drive unit 59 that controls the rotational speedand direction of the attached drive wheel 16. The integrated steeringand speed signal is affected by the steering input from steering inputdevice 24, if any, and the speed input of speed control device 71 (orspeed control device 79, as the case may be).

Integration link 44 can be moved from a neutral position toward driveunit 59 (toward the rear of vehicle 10). Such movement may becharacterized as being along the longitudinal axis of the integrationlink. With such movement, control mechanism 106 is manipulated so thatdrive unit 59 rotates its corresponding drive wheel 16 in a forwarddirection. Conversely, if integration link 44 is moved away from driveunit 59 from a neutral position, control mechanism 106 is manipulated sothat drive unit 59 rotates drive wheels 16 in a reverse direction. Ifintegration link 44 is not moved from a neutral position longitudinallytoward or away from drive unit 59, control mechanism 106 will not bemanipulated. Consequently, drive unit 59 will not cause forward orreverse rotation of drive wheel 16. In other embodiments, drive link 104may be coupled to control mechanism 106 such that rearward movement ofintegration link 44 causes reverse, rather than forward, rotation ofdrive wheel 16 (and forward movement of integration link 44 may causeforward rotation of drive wheel 16).

FIGS. 9-11 illustrate views of control system 40 with a full forwardspeed input from speed control device 71 and neutral, left turn, andright turn steering inputs, respectively, from steering input device 24.As shown in the comparison of FIGS. 6 and 9, when speed control device71 is provided with a forward speed input, outer ends 51 of slots 77 aremoved towards the rear of vehicle 10, and inner ends 49 of slots 77 aremoved towards the front of vehicle 10.

As shown in FIG. 9, with neutral steering and full forward input fromspeed control device 71, both integration links 44 are pushed toward therear of vehicle 10 an equal amount. With right and left integrationlinks 44 moved from a speed-neutral position toward drive units 59, bothdrive units 59 will cause drive wheels 16 to rotate in a forwarddirection. As shown in FIG. 9, steering input device 24 is in a neutralposition, therefore both front wheel assemblies 50 are positioned sothat the front wheels 18 would direct vehicle 10 straight ahead. In FIG.9, each integration link 44 is placed in an equivalent relative positionwithin slot 77. Therefore, each integration link 44 is moved anequivalent amount toward the rear of vehicle 10 when speed controldevice 71 is manipulated. As a result, the drive units 59 aremanipulated to rotate drive wheels 16 at equivalent forward rotationalspeeds. Drive wheels 16 will therefore work in conjunction with frontwheels 18 to cause vehicle 10 to maintain a forward path straight ahead.

However, as steering input device 24 is manipulated to cause a right orleft turn for vehicle 10, control system 40 causes right and left drivewheels 16 to rotate at different speeds. By rotating the right and leftdrive wheels 16 at different speeds, the drive wheels are able to assistvehicle 10 in turning. In particular, the outside drive wheel 16 (thedrive wheel farthest from the center of the turning arc) can rotate at afaster rotational speed than the inside drive wheel. In sharp turns, theoutside and inside drive wheels may also rotate in opposite directions.When the rotation of right and left drive wheels 16 is coordinated withthe angle of front wheels 18, vehicle 10 can make small- or zero-radiusturns and reduce the likelihood of a wheel skidding and damaging theturf or vegetation below vehicle 10.

Referring now to FIG. 10, speed control device 71 is placed in the fullforward position, and steering input device 24 has been manipulated sothat steering assembly 20 configures front wheel assemblies 50 for aleft turn. Control system 40 receives steering input from wheelassemblies 50 via flexible members 80. Control system 40 is thereforeconfigured for a full-forward speed left turn in FIG. 10. Comparing FIG.10 (full-forward speed left turn) to FIG. 7 (neutral speed input, leftturn), right integration link 44 has been shifted rearward from theneutral position in FIG. 7. In addition, left integration link 44 hasbeen shifted forward. As a result, right drive wheel 16 will rotate in aforward direction, while left drive wheel 16 will rotate in a reversedirection. This combined rotation of the drive wheels 16 in oppositedirections will assist vehicle 10 in making a small- or zero-radiusturn.

As shown in FIGS. 9 and 10, outer ends 51 (rather than inner ends 49) ofslots 77 are closer to the rear of vehicle 10. Therefore, as steeringinput device 24 is turned and integration links 44 are translated awayfrom the center of vehicle 10, integration links 44 and drive links 104will also be moved rearward towards the rear of vehicle 10. Each controlmechanism 106 will therefore also be rotated toward its respective driveunit 59, so that the forward rotational speed of each drive wheel 16 isincreased. Control system 40 is configured such that integration link 44associated with inner drive wheel 16 will be shifted forward more thanintegration link 44 associated with outer drive wheel 16. Consequently,the forward rotational speed of inner drive wheel 16 will be reducedmore than that of outer drive wheel 16. When steering input device 24 isprovided with a sufficient amount of input, the inner drive wheel 16will eventually cease forward rotation and begin reverse rotation. Thiscombined rotation of the drive wheels 16 in opposite directions willassist vehicle 10 in making a small- or zero-radius left turn.

Referring now to FIG. 11, control system 40 is configured for afull-forward speed input and a full right turn. This configuration isequivalent to FIG. 10, with the exception that steering input device 24(shown in FIG. 3) has been turned to the right instead of the left. Inthis configuration, right integration link 44 is positioned so thatright drive unit 59 will provide a reverse rotation of inner (right)drive wheel 16. Vehicle 10 can therefore perform a small- or zero-radiusturn to the right.

Referring now to FIGS. 12-14, speed control device 79 has beenpositioned to provide a reverse speed input to control system 40. InFIG. 12, control system 40 is configured for a neutral steering input.In FIGS. 13 and 14, control system 40 is configured for a left-turn anda right-turn, respectively. In FIGS. 12-14, speed input members 78 arepositioned so that inner ends 49 (rather than outer ends 51) of slots 77are closer to the rear of vehicle 10. Therefore, as integration links 44move inward (toward the center of vehicle 10) in response to a steeringinput, they will also move toward the rear of vehicle 10. As a result,control mechanism 106 will reduce the reverse rotational speed of eachdrive wheel 16. If a sufficient steering input is provided, integrationlink 44 associated with inside drive wheel 16 will be pushed far enoughrearward to cause inside drive wheel to cease reverse rotation and beginforward rotation. Inside drive wheel 16 can therefore rotate forward andoutside drive wheel 16 can rotate in reverse during a full turn with areverse speed input.

In FIG. 13, control system 40 is positioned for a left turn and speedcontrol device 79 is positioned for a reverse speed input. The leftintegration link 44 is pushed sufficiently rearward so that left(inside) drive wheel 16 will rotate forward. Right integration link 44is placed sufficiently forward so that outer (right) drive wheel 16 willrotate in reverse. With this configuration, vehicle 10 can make a smallor zero-radius reverse left turn.

Referring now to FIG. 14, control system 40 is positioned for a rightturn with speed control device 79 providing a reverse speed input. Theright integration link 44 is pushed sufficiently rearward so that right(inside) drive wheel 16 will rotate forward. Left integration link 44 isplaced sufficiently forward so that outer (left) drive wheel 16 rotatesin reverse. With this configuration, vehicle 10 can make a small- orzero-radius reverse right turn.

Referring now to FIG. 15, an alternate embodiment of the present controlsystems is shown. Control system 140 is similar to previously-describedcontrol system 40. Control system 140, however, does not comprise aflexible member or flexible members coupled to steering assemblies forfront steerable wheels. Instead, control system 140 comprises a steeringinput gear 180 operatively engaged with control member 181 (which, inthe depicted embodiment, is a geared member, like control member 81). Inexemplary embodiments, steering input gear 180 can be coupled to asteering input device (not shown) such as a steering wheel. Similar tothe previously described embodiment, control member 181 is operativelyengaged with integration members 136 (which, in the depicted embodiment,are geared members, like integration member 36), which are in turncoupled to integration links 144 via coupling members 145. Also similarto the previously described embodiment, integration links 144 arecoupled to speed input members 178, which are coupled to a speed inputdevice (not shown), including for example a throttle pedal. Eachintegration link 144 can be coupled to a drive unit (not shown), such ashydrostatic transmission or a drive unit that includes an electricmotor, in a manner similar to the previously described embodiment.

During operation, steering input gear 180 can be rotated (e.g., viarotation of a steering input device) such that control member 181 isalso rotated. The rotation of control member 181 also provides for therotation of integration members 136 such that rotation of control member181 also rotates integration members 136. The rotation of integrationmembers 136 provides for the lateral pivoting of integration links 144in a manner similar to the previously described embodiment. When speedinput members 178 receive a speed input, slots 177 of speed inputmembers 178 will be positioned at an angle such that lateral pivoting ofintegration links 144 will also provide a forward or rearwardtranslation of integration links 144. As described in the previousembodiment, the differentiation of the forward or rearward positioningof integration links 144 provides for different speed inputs to theright and left drive units and can assist in turning the vehicle.Control system 140 is suitable for use in any vehicle with drive unitsthat may be independently controlled to effect (or help effect) a turnof the vehicle.

Descriptions of well known manufacturing and assembly techniques,components and equipment have been omitted so as not to unnecessarilyobscure the present systems and devices in unnecessary detail. Further,the present systems and devices are not intended to be limited to theparticular forms disclosed. Rather, they are to cover all modifications,equivalents, and alternatives falling within the scope of the claims.

For example, the control members may be configured differently thanshown in the figures. In alternative embodiments, the integration memberthat is a rigid structure configured to affect the position of theintegration links relative to the speed input members of a given vehiclecontrol system can be a single structure, rather than two structures asshown in the depicted embodiment; for example, the integration membercan be a rigid structure that is connected to the control member androtates with it (like an angled bar pinned to the control member andhaving the same rotational axis as the control member) and that includescoupling members (or followers) that are positioned in the slots (orcams) of the integration links. Furthermore, the drive rods and theintegration links may be a single component rather than separatecomponents. In still other embodiments, the linkage coupling the speedcontrol device to the speed input members may be a differentconfiguration from that shown. For example, the linkage may be coupledto a single speed input member, which in turn provides an input to theother speed input member via a geared engagement at the ends of thespeed input members. As another example, in other embodiments, the guiderollers (shown but not labeled in the figures) that are adjacent theflexible members and proximate to the control member may be eliminated.

The appended claims are not to be interpreted as includingmeans-plus-function limitations, unless such a limitation is explicitlyrecited in a given claim using the phrase(s) “means for” and/or “stepfor,” respectively.

1.-17. (canceled)
 18. A vehicle control system comprising: a firststeering system for a first steerable wheel of a vehicle, wherein thefirst steering system comprises a first steering input member coupled toa steering input device; a control member coupled to the first steeringinput member such that the control member can receive a steering inputfrom the first steering input member when the vehicle is stationary; afirst integration link coupled to the control member and to a firstdrive unit; a second steering system for a second steerable wheel of thevehicle, wherein the second steering system comprises a second steeringinput member, and the control member is coupled to the second steeringinput member such that the control member can receive a steering inputfrom the second steering input member when the vehicle is stationary;and a second integration link coupled to the control member and to asecond drive unit.
 19. The vehicle control system of claim 18, whereinthe control member is configured to rotate as a result of receiving asteering input from the first steering input member.
 20. The vehiclecontrol system of claim 18, further comprising a first flexible memberconfigured to transmit a steering input from the first steering inputmember to the control member.
 21. The vehicle control system of claim18, wherein the first flexible member comprises a cable.
 22. The vehiclecontrol system of claim 18, wherein: the first steering system for thefirst steerable wheel comprises a first steering gear member coupled toa first wheel support; and the first steering input member isoperatively engaged with the first steering gear member; the secondsteering system for the second steerable wheel comprises a secondsteering gear member coupled to a second wheel support; and the secondsteering input member is operatively engaged with the second steeringgear member.
 23. (canceled)
 24. The vehicle control system of claim 18,further comprising a second flexible member configured to transmit asteering input from the second steering input member to the controlmember.
 25. The vehicle control system of claim 18, wherein the firstintegration link is coupled to a first drive unit and the secondintegration link is coupled to a second drive unit. 26.-32. (canceled)33. The vehicle control system of claim 18, further comprising: a firstspeed input device coupled to a first speed input member; and a firstintegration member coupled to the first speed input member through thefirst integration link. 34.-35. (canceled)
 36. A vehicle control systemcomprising: a control member that will move as a result of movement of asteering input device; a first integration link coupled to the controlmember and to a first drive unit; and a first integration member coupledto the first integration link such that rotational movement of thecontrol member will cause movement of the first integration member,which will cause movement of the first integration link; wherein thefirst integration member is not attached to a rigid link that extendsforward of the control member.
 37. The vehicle control system of claim36, further comprising: a second integration link coupled to the controlmember and to a second drive unit. 38.-40. (canceled)
 41. The vehiclecontrol system of claim 36, further comprising a second integrationmember operatively engaged with the control member and coupled to thesecond integration link such that rotational movement of the controlmember will cause movement of the second integration member, which willcause movement of the second integration link.
 42. The vehicle controlsystem of claim 41, further comprising: a first coupling member couplingthe first integration member to the first integration link; and a secondcoupling member coupling the second integration member to the secondintegration link; wherein at least a portion of the first couplingmember is positioned in a slot of the first integration link and atleast a portion of the second coupling member is positioned in a slot ofthe second integration link. 43.-44. (canceled)
 45. The vehicle controlsystem of claim 36, further comprising: a first speed input devicecoupled to a first speed input member; wherein the first integrationmember is coupled to the first speed input member through the firstintegration link. 46.-47. (canceled)
 48. A vehicle control system for avehicle with left and right steerable wheels, the vehicle control systemcomprising: a control member that will move as a result of movement of asteering input device; a first integration link coupled to the controlmember and to a first drive unit; and a first integration member coupledto the first integration link such that rotational movement of thecontrol member will cause movement of the first integration member,which will cause movement of the first integration link; wherein thevehicle control system is configured so as to not send a steering signalforward of the control member to either a first steering input gear forthe first steerable wheel or a second steering input gear for the secondsteerable wheel.
 49. The vehicle control system of claim 48, furthercomprising: a second integration link coupled to the control member andto a second drive unit. 50.-53. (canceled)
 54. The vehicle controlsystem of claim 53, further comprising: a first coupling member couplingthe first integration member to the first integration link; and a secondcoupling member coupling the second integration member to the secondintegration link; wherein at least a portion of the first couplingmember is positioned in a slot of the first integration link and atleast a portion of the second coupling member is positioned in a slot ofthe second integration link.
 55. (canceled)
 56. The vehicle controlsystem of claim 54, wherein the first and second integration members areconfigured to rotate in the same plane in response to a rotation of thecontrol member.
 57. The vehicle control system of claim 48, furthercomprising: a first speed input device coupled to a first speed inputmember; wherein the first integration member is coupled to the firstspeed input member through the first integration link.
 58. The vehiclecontrol system of claim 57, wherein the first speed input memberincludes a slot.
 59. The vehicle control system of claim 58, wherein thefirst integration link is coupled to the first speed input member so asto be capable of affecting a position of the slot. 60.-71. (canceled)